Camera exposure control



March 25, 1952 D. B. DORSEY CAMERA EXPOSURE CONTROL 2 SHEETSSHEET 1Filed July 1, 1948 DA mar/r f/QI'OFLDOD SUPER N Supra nan VERm/nmE PA myfan K0 DA cm OR IN V EN TOR. 25727236 3 D0 2 SHEETSSl-IEET z IIIILIIIIID. B. DQRSEY CAMERA EXPOSURE CONTROL March 25, 1952 Filed July 1, 1948Patentecl Mar. 25, 1952 UNITED STATES PATENTOFFICE CAMERA EXPOSURECONTROL Dennis E. Dorsey, Chicago, Ill.

Application July 1, 1948, Serial No. 36,500

1 Claim. 1

This invention relates to camera controls.

It is a principal object of this invention to provide simple andinexpensive means in and for a camera for determining the proper settingof the shutter opening by the selection of the shutter speed, or viceversa, and in accordance with the measured light conditions, the filmspeed rating and filter factor.

It is a further object of the invention to provide in a camera means foradjustably relating the shutter speed setting to the shutter openingsetting in such a manner that one of said settings will determine theother setting in accordance with the measured light conditions.

In the taking of successful pictures under all of the various conditionsand on all of the various different speed films, it is necessary for thephotographer first to measure the light conditions to obtain a lightrating and thereafter utilizing that rating to set a complicated seriesof dials having complex scales to determine the shutter openings fordifferent speed settings and different film speed ratings and filterfactors. It frequently happens that the shutter opening when finallydetermined is beyond the range of the camera which is possessed by thephotographer and the complicated series of operations must be repeatedfor a slower or faster shutter speed until a shutter opening figure isobtained for which the camera can be set. This method of determining theproper setting is always irksome to the amateur photographer; a sourceof great annoyance to those being photographed, particularly children,and requires so much time to perform that activity pictures are lost ortaken at haphazardly chosen settings. It is accordingly an object ofthis invention to provide an exposure setting guide and control properlyrelating all the various factors so that in order to take a picture itis merely necessary to measure the light conditions to obtain a lightrating figure and then set the guide so that that figure is brought intoregistry with the shutter speed setting and thereupon the shutteropening setter will be positioned for taking the picture at the propershutter opening.

ther and further objects and advantages of the invention will beapparent from the following description when taken in connection withthe accompanying drawings wherein:

Fig. 1 is a fragmentary view in elevation oi a camera embodying theinvention;

Fig. 2 is a view in rear elevation of a camera embodying the invention;

Fig. 3 is a fragmentary view in section taken along the line 33 of Fig.1;

Fig. 4 is a fragmentary view in horizontal section taken substantiallyalong the line 4-4 of Fig. 1;

Fig. 5 is a fragmentary view in perspective of another type of cameraembodying the present invention; and

Figs. 6 and '7 are fragmentary views in plan and elevation respectivelyof still another type of camera embodying the invention.

As shown in Figs. 1 to 4, a bellows, or other between the lens, typecamera embodying the present invention may comprise an exposure guidecontrol means '2 in the form of a disk 4 mounted on the lens housingtube 6 as by ring 8 or other suitable retainer threaded or otherwisefitted on the lens tube. The lens tube is mounted in a conventionalmanner on the forward end of the bellows l0 and carries an exposure timesetter l2 and an exposure opening control l4 connected in the usualmanner to the usual exposure timer and the usual iris diaphragmcontrolling the size of the shutter opening. The exposure time setter 12has the usual pointer it which cooperates with a shutter speed scale ISon the periphery of the conventional drum 26 and the shutter openingcontrol l4 has the usual pointer 22 which cooperates with the usualscale 25 on the surface of a ring or disk which encompasses the lenstube 6 and closes or forms the forward end of the drum 20.

It should be noted that the camera illustrated is of thetype, well knownin the prior art, in which the angular adjustments of the time setter l2and the opening control M are equal, i. e., the numbers of each scale,!8 and 25, are equally spaced and the arcuate movement of the pointer I6from one scale number to the next is equal to the arcuate movement ofthe pointer 22 from one scale number to the next.

The exposure opening control l4 extends in the usual manner through asuitable slot, not shown, in the periphery of the drum 25 so as tocontrol the setting of the diaphragm that determines the size of theshutter opening. The disk 4 is mounted on the lens tube 6 in position tocooperate with the pointers it and 22, the pointer H5 being for thatpurpose provided with a depending portion or tip 24 extending over thedisk 4 and cooperating with a light rating scale 2%. The pointer- 22 forthe exposure opening control l4 extends over the exposure opening scale25 on the front face of the drum 20 at the bottom thereof and isprovided with a resilient or flexible tip portion 28. The disk 4 isformed with segmentally cut out section exposing the scale 25 and anarcuate axially dicamera.

rected rim portion or flange 30 having a series of angularly spacednotches 32 cooperating with an emulsion rating and filter factor scale33 marked on the surface of the disk adjacent the arcuate axiallydirected rim portion 3&3.

The resilient pointer portion 28 with the exposure opening pointer 22 ispositioned and shaped for detachable reception in the notches 3'2 andreadily disengaged by inserting the fingernail under it and lifting itout of the notch into which it may be engaged at any time.

As shown in Fig. 2, the rear face of the camera is provided with a filmrating, filter factor chart 36 specifying for each of the best knownfilms the proper speed rating for daylight and photoflood use and thevarious speed ratings of each of the films when taking a picture eitherunder daylight or photofiood conditions and by the use of any of themost commonly used filters.

'As shown in that chart, for example, the film speed rating for Super XXfilm when used under daylight conditions and without a filter is 100,while used without a filter under photofiood conditions is 64, and thefilter factor ratings for difierent filters used under the two differentlighting conditions varies from 8, which is the speed film rating usingan A filter under photofiood lighting conditions, to 64, which is thefilm speed rating when using a K1 filter under daylight conditions.

The filrn speed ratings shown in the chart of Fig. 2 are taken orcalculated from the Weston ratings but it is to be understood that suchratings may be taken or calculated from any other known system of basicfilm speed ratings.

Similar ratings are provided for the other most popular types of filmsuch as the Ultra Speed Pan, the Super Pan Press, the Plus X, theSupreme, the Superior Pan 2, the Verichrome, the Plenachrome, thePanatomic X, the Kodacolor, the Kodachrome and Ansco Color for daylightuse, and the Kodachrome and Ansco Color for artificial light.

The scale 34 is composed of the ratings taken from the chart to, thevarious indicia of the scale being appropriately related as by thelocation of the flexible portion 28 of the exposure opening control i iwith the selected notch corresponding to the film speed rating.

The stamping of the annular, axially directed rim 36 from the peripheryof the disk 5; leaves an arcuate recess in the rim of the diskuncovering the exposure opening scale 25 so that the pointer 25 alsocooperates with that scale to indicate the exposure opening setting.

In use, the flexible pointer 28 is set notch 32 corresponding to thefilm speed rating applicable to the particular type of film in the Thisis preferably done at the time the film is placed in the camera. If thecamera is normally or most frequently used for taking pictures indaylight or under photoflood conditions, the pointer is accordingly setin the notch corresponding to the appropriate film speed rating. If thepictures are most usually taken with a particular filter on the camera,the pointer is correspondingly set for the appropriate film speed ratingwhich takes into account the filter factor for that usually employedfilter. Whatever may be the usual circumstances which govern the initialsetting of the pointer, that setting may be readily changed when it isdesired to take pictures under difierent lighting conditions, i. e.,daylight or photofiood, or with different filters.

into a When it is dered to take a picture it is then .ierely necessaryto measure the prevailing light conditions, by the usual photometer orlight meter and read from the meter the light rating. The disk 4 maythen be turned to bring the same light rating of scale 28 into registrywith the pointer 2 of the time exposure setter 12. This turning of thedisk 4 automatically causes turning of the exposure control Hi to theproper exposure opening setting as indicated by the exposure openingscale 25.

If, subsequently, the time exposure setting is varied by turning thetime exposure setter i2, it is merely necessary to turn the disk t tobring that light rating of scale to the new setting of the pointer 2 andthis turning of the disk automatically sets the exposure control it tothe roper position.

It is frequently desirable to select the shutter or exposure opening andthereafter to set the shutter speed to the proper value required fortaking the picture at the selected shutter opening. It will be evidentthat such cases the pointer 22 may be initially set at such a selectedshutter opening, thereby presetting the disk l. Accordingly, when thescene brightness or light rating is determined or measured by theexposure meter then the pointer it may be adjusted until its tip 24 isaligned with the number of the scale 25 corresponding to the value ofscene brightness or light rating as read directly from the exposuremeter.

It should be noted that as seen in Fig. 4, the time speed setting scaleIt includes time exposure intervals from one-half a second to eightseconds or longer. In a common form of the camera illustrated in Fig. 4,the slowest instantaneous exposure which can be taken is onetwenty-fifth of a second. For taking longer exposures, it is desirablefor the photographer to have some indication of the proper time andexposure opening needed at the measured scene brightness and inaccordance with the speed rating or filter factor of the film.Accordingly, applicant extends the usual shutter speed scale by theaddition of the time exposure determining numbers from one-half a secondto eight seconds or to sixteen seconds or to thirty-two seconds, etc.,as may be appropriat for the particular camera. Accordingly, when thescene brightness or light rating as measured by t .e exposure meter isof such low value, that an exposure longer than slowest shutter speed isrequired, alignment of the scene brightness or light rating number ofscale 26 with the time exposure numbers of the scale !6 serves toindicate the proper interval for the time exposure at the previouslyselected shutter opening or at the maximum permissible shutter opening,if it is desired to make the time exposure as short as possible. Theprevious selection of the maximum shutter opening will set the controldisk 4 to a certain position and the alignment of the subsequentlydetermined scene brightness of scale 26 with the time exposure intervalsof scale l3, will indicate the shortest possible exposure interval.

If, however, it is desired to take a picture at a previously selectedtime exposure interval, the turning of the disk i to bring thedetermined scene brightness rating of scale 25 into alignment with thatselected time exposure interval will automatically set the exposureopening to the proper value.

In the embodiment shown in Fi 5, a moving picture camera 38 having anexposure opening control ring surrounding the lens tube 42 is providedwith an exposure guide or control disk 44 similar to the disk 4 andmounted on the lens tube between the adjusting ring 48 and the frontwall 45 of the camera. If the movie camera 38 is of the variable speedtype adjustable to take pictures at different timing speeds, the frontwall 45 of the camera is provided with or has inscribed thereon suitablepointers 48 adjacent the periphery of the disk 44 and marked with asuitable frames per second scale 58. The exposure control ring 40carries the usual resilient pointer 52 which cooperates with the'usualarcuately arranged exposure opening scale 54 on the front wall 46 of thecamera. Pointer 52 also cooperates with and is selectively receivable innotches 56 of an annular, axially directed rim portion 58 of the disk44. The notches 56 cooperate with a film speed rating scale 6|)inscribed on the surface of the disk 44 adjacent and within the annularflange portion 58. The disk 44 is also provided with a light ratingscale 82 which cooperates with the pointers 48 of the frames per secondscale 58.

The exposure guide and control shown in Fig. 5 operates similarly tothat shown in Figs. 1 to i. A light rating number determinative of thelight conditions is determined by the usual exposure meter and thecorresponding number of the light rating scale 62 on the disk 44 is setopposite the pointer 48 corresponding to the frames per second for whichthe camera is set. The pointer 52 of the exposure opening control ring48 having previously been set into the notch opposite the proper filmspeed rating and filter factor number of scale 68, the rotation of thedisk to align the proper light rating number of scale 62 with theappropriate frames per second pointer automatically sets the exposureopening control ring at the proper exposure opening as indicated on thefixed scale 54 by the pointer 52.

In the embodiment shown in Fi s. 6 and 7, a camera of the focal planeshutter and interchangeable lens type is supplied with the usualexposure time setter 66 located on the top wall of the camera and adetachable, interchangeable lens 68 including a diaphragm openingcontrol ring it, the unit with the control ring 18 rotatably mountedthereon being detachably associated in the usual manner with a receivingtube 14 in and projecting slightly forward from the front wall 16 of thecamera. An exposure guide control means in the form of a disk (8 inevery respect, except size, identical to the exposure guide control disk44, is mounted on the projecting portion of the receiving tube 14 forthe lens unit and is secured thereon against axial movement by athreaded collar 88, the forward end portion of the tube being externallythreaded to receive the internally threaded clamping ring 8. The disk 18is of course mounted for free rotation on the tube 74 and its notchedarcuate flange portion 82 cooperates with a resilient pointer 84 carriedby the diaphragm opening control ring 10 to set the diaphragm opening.The disk 78 is provided with the light rating scale 85 corresponding tothe scale 62 of the exposure disk 44 of Fig. 5 and a film speed ratingscale 88.

The front wall 16 is provided with an arcuate exposure timing scale 98about the periphery of the disk 18, the scale 98 conforming to the scaleof the exposure time setter 86 on the top wall of the camera. Theforward wall 16 of the camera is also provided with a diaphragm openingscale 92 extending arcuately of the disk 18 in juxtaposition to thearcuate flange 82 of the disk and cooperating with the pointer 84 of thediaphragm opening control ring 10.

The use of the exposure guide and control means 01' disk 18 in the formof the invention shown in Figs. 6 and '7 is the same as with theembodiment shown in Fig. 5, the pointer 84 being set, when the camera isinitially loaded, into the notch of the arcuate flange 82 correspondingto the film speed rating and filter factor of the film employed and thefilter commonly used with that film. The exposure time setter 66 is ofcourse set to take any particular picture at the most desirable speed ortime interval and a light rating number having been determined by use ofan exposure meter, the correspondin light ratim number of scale 36 isset by rotation of the disk 18 in alignment with the exposure intervalindicated by scale 98 and corresponding to the setting of the exposuretime setter 66. This rotation of the disk 18 automatically effectsproper setting of the exposure or diaphragm opening .by causing rotationof the diaphragm opening control ring 10.

As described with reference to Figs. 1 to 4, the disk i8 may also beused to determine the proper shutter speed setting from a previouslyselected shutter opening setting.

It should be noted that the exposure timing scale 98 is extended toinclude time exposure determining intervals, similarly to the scale i 8of the camera shown in Figs. 1 to 4, which time exposure numbers on thescale cooperate with the light rating scale 86 of the disk 18 toindicate to the photographer the proper time exposure intervalsaccording to the exposure opening settings.

A very important feature of applicants invention resides in the factthat the means used for automatically setting the exposure opening inaccordance with the time speed setting, or determining the proper timespeed setting from a previously selected exposure opening setting, doesnot interfere in any way with the normal use of the camera for takingphoto-flash pictures.

It will be evident from the foregoing that applicant has provided asimple and inexpensive means in and for a camera for determining theproper setting of the shutter opening in accordance with the selectedshutter speed, the measured light conditions, the film speed rating andfilter factor; means for adjustably relating the shutter speed settingto the shutter opening setting in such a manner that setting of suchmeans in respect to the selected shutter speed setting in accordancewith the measured light conditions will automatically select the propershutter opening for taking the picture, and an exposure setting guideand control properly relating all the various factors so that in orderto take a picture it is merely necessary to measure the light conditionsto obtain a light rating or scene brightness figure and then set theguide sothat that figure is brought into registry with the shutter speedsetting and thereupon the shutter opening setter will be positioned fortaking the picture at the proper shutter opening.

It will be obvious that changes may be made in the form, constructionand arrangement of the parts without departing from the spirit of theinvention or sacrificing any of its advantages, and the right is herebyreserved to make all such changes as fairly fall within the scope of thefollowing claim.

What I claim is:

-In a shutter type camera having a lens tube, an exposure time setteradjustable arcuately about the aXis of the lens tube, a shutter speedscale with which said time setter cooperates, an exposure opening setteroppositely positioned on the opposite side of said lens tube from saidtime setter and also adjustable arcuately about the axis of said lenstube, an exposure opening scale with which said exposure opening settercooperates, an exposure control ring shiftably mounted on said lens tubeand having a light rating scale alignable with the time setter to aligna number of said scale corresponding to light rating conditions with thetime setter, said control ring having a film speed scale and an arcuatenotched segment adjacent the exposure opening scale, said exposureopening setter including a resilient arm portion providing an indicatorfor said film speed scale and said exposure opening scale, said armtraversing said arcuate segment and selectively engageable with thenotches therein and normally maintained in locked engagement with anotch corresponding to th predeter- 8 mined setting of the arm withrespect to the film speed scale whereby the ring and exposure openingsetter and arm are rotated in unison upon variation of the relativesettings of the light rating scale and the shutter speed scale.

DENNIS B. DORSEY.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 883,607 Andrews Mar. 31, 19081,543,208 Fairchild June 23, 1925 1,623,998 Cooke Apr. 12, 19272,105,631 Becker Jan. 18, 1938 2,222,298 Nerwin 1 Nov. 19, 19402,343,257 Hineline Mar. '7, 1944 FOREIGN PATENTS Number Country Date303,088 Germany Jan. 18, 1918

